Antennas in satellite-communication may include a maximum regulatory compliant equivalent isotropic radiated power spectral density (EIRP-SD) in a transmitting frequency band of the antenna. This may be achieved by an amplitude distribution in an aperture plane of the antenna. In array antennas, aperture illumination may be implemented by a power divider network, which may excite the single radiating elements of the antenna array. Inputs and outputs of a power divider may be designed such that an asymmetrical power distribution creates conditions for desired aperture illumination.
A homogeneous aperture illumination may be desirable for receiving characteristics of the array antenna, because homogeneous aperture illumination may maximize antenna gain. If a shared power divider network is used for the transmitting band and the receiving band, however, this may result in a reduced performance capability of the array antenna in the reception case due to an inhomogeneous power divider network used in the transmitting frequency band.
WO 99/34477 describes a power divider where impedance matching, and consequently, power division, may be optimized by way of the location and size of constrictions. U.S. Pat. No. 4,365,215 and Hee-Ran Ahn; Wolff, I., “General design equations, small-sized impedance transformers, and their application to small-sized three-port 3-dB power dividers”, Microwave Theory and Techniques, Transactions on, Vol. 49, No. 7, pages 1277 to 1288, July 2001, describe design suggestions for power dividers.